1. Field
A photostimulation apparatus is disclosed.
2. Description of the Related Art
Recently, light-sensitive proteins activating or inhibiting nerve cells in response to light with specific wavelength have been developed in the field of brain study. Using the light-sensitive proteins, it is possible to control the nerve cells in the neural circuitry more freely and elaborately. With the conventional electrical microstimulation using a micro-stimulant, target nerve cells can be activated only. For the study of the neural circuitry, it is required to stimulate specific cells and to measure response from nerve cells in other area resulting from the inter-connection inside the neural circuitry, at the same time. With an artificial electrical stimulation, it is difficult to measure the subtle electrical physiological response from other cells because of noise.
In contrast, with photostimulation, the target nerve cells can be selected freely through selection of promoters. Once light-sensitive proteins are expressed in the target nerve cells, both activation and inhibition can be controlled freely by controlling the wavelength of photostimulation. Accordingly, with photostimulation, the neural circuitry can be studied more elaborately and systematically. Moreover, it may be helpful in studying how a specific neuropsychiatric disease is connected with specific brain nerve cells and how it causes problems in the neural circuitry, as well as in treating the disease. Especially, in clinical practice, whereas the conventional deep brain stimulation technique allows only activation of nerve cells through electrical stimulation, the photostimulation technique allows both activation and inhibition. Hence, it may provide an epoch-making turning point in the treatment of neuropsychiatric diseases.
The cerebral cortex of the human brain is a region that plays a key role in memory, attention, perceptual awareness, thought, language, and consciousness. It constitutes the outermost layer of the cerebrum. The functions of the areas of the cerebral cortex are well known. Located right beneath the skull, the cerebral cortex may be easily damaged by accidents or diseases. On the other hand, accessibility to treatment is relatively high because it is located at the outer side of the brain. Therefore, the cerebral cortex makes a good target for neural photostimulation.